| Jendarmar Ltd | Real estate | 2014 |
| Jenkinsons Glaziers & Upvc NE Ltd | Construction | 2022 |
| Jesres (Property Lets) Co. Limited | Real estate | 1996 |
| Jfcm Prime Holdings Limited | Wholesale & retail | 2026 |
| JG Seafoods Limited | Wholesale & retail | 2012 |
| JGR Industries Ltd | Professional & scientific | 2026 |
| JH Premier Property Services Ltd | Real estate | 2026 |
| Jhfitness Limited | Arts & recreation | 2026 |
| Jimmy Denley Ltd | Manufacturing | 2024 |
| Jimmy's at Tynemouth Station Limited | Wholesale & retail | 2023 |
| Jing Well Ltd | Health & social care | 2015 |
| JJ Corporation Ltd | Financial services | 2024 |
| JJM Tile Agency Limited | Wholesale & retail | 2014 |
| JJS Lifting Ltd | Extraterritorial | 2024 |
| JL Blue Holdings Limited | Real estate | 2021 |
| JL Surveying Services Ltd | Professional & scientific | 2013 |
| JLB Creative Limited | Administrative & support | 2023 |
| JLB Operations Limited | Professional & scientific | 2024 |
| JLF Enterprises Ltd | Financial services | 2015 |
| JLP Support Services Limited | Administrative & support | 2026 |
| JM Electrical Solutions NE Ltd | Construction | 2026 |
| JM Property (NE) Ltd | Real estate | 2025 |
| JM Robertson Services Ltd | Manufacturing | 2022 |
| JMA Contract Services Limited | Professional & scientific | 2014 |
| Jmcc Properties Ltd | Real estate | 2025 |
| JMP Concerts Ltd | Arts & recreation | 2025 |
| JMP Developments (NE) Ltd | Real estate | 2026 |
| JN Access Limited | Construction | 2015 |
| JO Gipson Physiotherapy Limited | Health & social care | 2026 |
| JOE Stone Design Ltd | Arts & recreation | 2023 |
| Joes Driving Solutions Limited | Transport & logistics | 2026 |
| John Jubb Construction Services Limited | Construction | 2014 |
| John Lightbown & Sons Organ Builders Limited | Manufacturing | 2002 |
| John Lilley & Gillie Limited | Manufacturing | 2016 |
| John Wilkinson Financial Planning Ltd | Financial services | 2021 |
| John Wilson Joinery Ltd | Construction | 2016 |
| Joint Education Team LLP | | 2022 |
| Jomoga Ltd | Health & social care | 2014 |
| JON Storey Ltd | Other services | 2019 |
| Jonathan Graham Limited | Information & communication | 2000 |
| Jones & Co Ventures Ltd | Administrative & support | 2017 |
| Jones Joinery North-East Ltd | Manufacturing | 2022 |
| Jones Smith Properties Limited | Real estate | 2023 |
| Jonluke Mckie Arts Ltd | Arts & recreation | 2026 |
| Jordan Peters Ltd | Construction | 2014 |
| Jose Ucar Ltd | Professional & scientific | 2023 |
| Joseph Richmond & Sons Limited | Manufacturing | 2010 |
| JP Lifecare Limited | Administrative & support | 2026 |
| JP Personalised Services Limited | Health & social care | 2022 |
| JP Sales Solutions Ltd | Professional & scientific | 2023 |
| JPG Holdings Ltd | Financial services | 2015 |
| JPM Autobodies Truck and Van Limited | Energy | 2019 |
| JPT International Ltd | Financial services | 2024 |
| JRB Services NE Ltd | Administrative & support | 2026 |
| JRP Consulting Ltd | Hospitality | 2021 |
| Jsff Limited | Hospitality | 2023 |
| Jsmt Consulting Limited | Wholesale & retail | 2023 |
| JSX Entertainment Limited | Professional & scientific | 2023 |
| JT Chance Ltd | Construction | 2018 |
| JT Welding Limited | Construction | 2020 |
| Jtcr Investments Limited | Arts & recreation | 2025 |
| Jtwengineering Ltd | Manufacturing | 2025 |
| Jubb Bros Ltd | Real estate | 2022 |
| Jubb Holdings Ltd | Financial services | 2025 |
| Juicy Fitness Ltd | Arts & recreation | 2018 |
| Juli MAC Design & Print Ltd | Arts & recreation | 2025 |
| Julie Chambers Design Limited | Professional & scientific | 2026 |
| Jump for FUN Racing Limited | Arts & recreation | 2005 |
| Junella 55 Degrees Limited | Real estate | 2003 |
| JW Contracting Ltd | Professional & scientific | 2022 |
| JW Short Stays Ltd | Households | 2024 |
| JWM Estates Limited | Real estate | 2021 |
| K & I Consulting LLP | | 2020 |
| K & R Traders Ltd | Wholesale & retail | 2019 |
| K & S Tynemouth Ltd | Real estate | 2026 |
| K F MAY Ltd | Mining & quarrying | 2023 |
| K G Burns Consultancy Limited | Professional & scientific | 2024 |
| K G Distributors Ltd | Wholesale & retail | 2015 |
| K G Properties (Northern) Limited | Real estate | 2016 |
| K R Pearce Ltd | Construction | 2025 |
| K Winter Groundworks Ltd | Construction | 2026 |
| K&Co Hair Ltd | Other services | 2025 |
| K.A.N.E Commercial Limited | Financial services | 2025 |
| K.C.H Property Services Ltd | Construction | 2026 |
| Kairos Metering Group Ltd | Professional & scientific | 2023 |
| Kalm Ventures Limited | Real estate | 2018 |
| Kappa Technology Consulting Ltd. | Professional & scientific | 2019 |
| Karazin International University (Ukraine) Limited | Education | 2026 |
| Karimah Tandoori Ltd | Hospitality | 2021 |
| Karma Coast Collective Community Interest Company | Health & social care | 2024 |
| Karma Coast Ltd | Wholesale & retail | 2019 |
| Katie Crosby Ltd | Professional & scientific | 2020 |
| Kaysafe Engineering Limited | Wholesale & retail | 1992 |
| Kc&G Limited | Financial services | 2016 |
| Kced Limited | Health & social care | 2018 |
| KCS Northumberland Limited | Administrative & support | 2021 |
| KD Consulting Limited | Professional & scientific | 2023 |
| Keane & Cahill Limited | Real estate | 2025 |
| Keddie Pedi Limited | Health & social care | 2020 |
| Keeping Families Together Ltd | Health & social care | 2025 |